Use json.loads
a = ['{"primaryDocument": "Aurum1.pdf", "matchesWithDocument": "Aurum2.pdf", "primaryDocumentOverlay": {"page": 1, "top": null, "left": null, "width": null, "height": null}, "matchesWithDocumentOverlay": {"page": 1, "top": null, "left": null, "width": null, "height": null}, "similarityIndex": 0.9993153342654213, "isSimilar": true}', '{"primaryDocument": "Aurum1.pdf", "matchesWithDocument": "Aurum2.pdf", "primaryDocumentOverlay": {"page": 2, "top": null, "left": null, "width": null, "height": null}, "matchesWithDocumentOverlay": {"page": 2, "top": null, "left": null, "width": null, "height": null}, "similarityIndex": 0.9983211993255433, "isSimilar": true}', '{"primaryDocument": "Aurum1.pdf", "matchesWithDocument": "Aurum2.pdf", "primaryDocumentOverlay": {"page": 21, "top": null, "left": null, "width": null, "height": null}, "matchesWithDocumentOverlay": {"page": 2, "top": null, "left": null, "width": null, "height": null}, "similarityIndex": 0.997596096801685, "isSimilar": true}', '{"primaryDocument": "Aurum1.pdf", "matchesWithDocument": "Aurum2.pdf", "primaryDocumentOverlay": {"page": 3, "top": null, "left": null, "width": null, "height": null}, "matchesWithDocumentOverlay": {"page": 3, "top": null, "left": null, "width": null, "height": null}, "similarityIndex": 0.9988208175324497, "isSimilar": true}', '{"primaryDocument": "Aurum1.pdf", "matchesWithDocument": "Aurum2.pdf", "primaryDocumentOverlay": {"page": 4, "top": null, "left": null, "width": null, "height": null}, "matchesWithDocumentOverlay": {"page": 4, "top": null, "left": null, "width": null, "height": null}, "similarityIndex": 0.9960270471399298, "isSimilar": true}']
output = [json.loads(i) for i in a]
output
[{'primaryDocument': 'Aurum1.pdf',
'matchesWithDocument': 'Aurum2.pdf',
'primaryDocumentOverlay': {'page': 1,
'top': None,
'left': None,
'width': None,
'height': None},
'matchesWithDocumentOverlay': {'page': 1,
'top': None,
'left': None,
'width': None,
'height': None},
'similarityIndex': 0.9993153342654213,
'isSimilar': True},
{'primaryDocument': 'Aurum1.pdf',
'matchesWithDocument': 'Aurum2.pdf',
'primaryDocumentOverlay': {'page': 2,
'top': None,
'left': None,
'width': None,
'height': None},
'matchesWithDocumentOverlay': {'page': 2,
'top': None,
'left': None,
'width': None,
'height': None},
'similarityIndex': 0.9983211993255433,
'isSimilar': True},
{'primaryDocument': 'Aurum1.pdf',
'matchesWithDocument': 'Aurum2.pdf',
'primaryDocumentOverlay': {'page': 21,
'top': None,
'left': None,
'width': None,
'height': None},
'matchesWithDocumentOverlay': {'page': 2,
'top': None,
'left': None,
'width': None,
'height': None},
'similarityIndex': 0.997596096801685,
'isSimilar': True},
{'primaryDocument': 'Aurum1.pdf',
'matchesWithDocument': 'Aurum2.pdf',
'primaryDocumentOverlay': {'page': 3,
'top': None,
'left': None,
'width': None,
'height': None},
'matchesWithDocumentOverlay': {'page': 3,
'top': None,
'left': None,
'width': None,
'height': None},
'similarityIndex': 0.9988208175324497,
'isSimilar': True},
{'primaryDocument': 'Aurum1.pdf',
'matchesWithDocument': 'Aurum2.pdf',
'primaryDocumentOverlay': {'page': 4,
'top': None,
'left': None,
'width': None,
'height': None},
'matchesWithDocumentOverlay': {'page': 4,
'top': None,
'left': None,
'width': None,
'height': None},
'similarityIndex': 0.9960270471399298,
'isSimilar': True}]